Throughout this specification and claims the term “fluid rotary machine” is intended to include both rotary motors and rotary pumps.
Fluid rotary machines have been known and used in various industries ever since the industrial revolution. In general terms, to operate as a motor, a high pressure fluid is feed through the machine and the pressure of the fluid used to impart motion to mechanical components to generate a mechanical kinetic energy that is then used to power or drive some other machine. When used as a pump, mechanical power is imparted to mechanical components of the pump which displace or force fluid through various ports to create a fluid flow and thus a pumping action.
The Applicant has been particularly innovative in the design and manufacture of fluid rotary machines particularly, although not exclusively, for use as motors in oil and gas drilling. One example of such is the hydraulic motor is described in International Application No PCT/AU97/00682. A substantial benefit of the motor described in the aforementioned application is that in comparison with other known motors, it has a substantially higher power density or power to weight ratio. This enables the motor to be of a significantly shorter length for the same power output in comparison to a convention motor. This allows greater precision in directional control of the drill and the ability to turn at substantially smaller radii than can be achieved with the prior art.
Notwithstanding the substantial benefits of the motor described in the abovementioned international application, the Applicant continues to conduct research and development for the purposes of producing a smaller, shorter and simpler fluid rotary machine with higher power density than is currently available. This research and development has lead to the invention described herein.